The present invention relates to pipe testing apparatus, and more particularly to improved apparatus for providing fluid pressure within a pipe to test for leakage, structural integrity, etc.
It is known to pressure-test pipes by introducing fluid under pressure into a pipe having sealed ends. However, if a pipe is of relatively large diameter and long length, considerable fluid pressure will develop against plates or caps which seal the ends of the pipe. Additionally, it is costly and time consuming to provide a large volume of fluid within the pipe. To overcome these problems, there have been proposals to insert a mandrel within a pipe to be tested.
With a mandrel inserted in a pipe, fluid may be introduced between the outer surface of the mandrel and the inner diameter of the pipe. Less fluid is required because of the volume occupied by the mandrel, and pressures exerted on caps covering the end of the pipe will be correspondingly decreased. Also, the time required to introduce and withdraw a fluid, such as water, will be decreased.
There are, however, certain deficiencies present in prior art systems which employ a mandrel within a pipe for testing. First of all, the mandrel must be provided with seals at both of its ends in order to produce a fluid-sealed condition between the ends of the mandrel and the ends of the pipe. Such a mandrel is adequate for testing only a given pipe length. If a long pipe is to be tested, the mandrel must be moved in stages throughout the length of a pipe with testing being done at each individual stage. This procedure is time consuming and expensive.
Additionally, difficulties arise when the mandrel is to be used in testing pipes having different sized diameters. Prior art devices attempt to solve this problem by providing complex expandable and contractable sealing mechanisms.
Accordingly, it is a general object of the present invention to provide a pipe-testing apparatus which is readily adapted to test the entire length of pipes of varying diameters and lengths, including relatively long lengths and large diameters.
More particularly, the present invention provides an apparatus which includes a first, fixed sealing means for sealing one end of a mandrel. A second, shiftable sealing means is adapted to advance a pipe so that the non-sealed mandrel end is inserted through one end of the pipe to a testing position. The shiftable sealing means urges the other end of the pipe against the first sealing means. The shiftable sealing means includes a pressure plate and a plug, the pressure plate sealing one end of the pipe and the plug being insertable within the open end of the mandrel for sealing it. In the testing position, both ends of the mandrel and pipe are sealed. The pressure plate is sized to seal pipes of varying diameters, and the mandrel may include detachable sections to accommodate different lengths of pipe.
Another object of the present invention is to provide a relatively simple pipe-testing apparatus in which the fixed sealing means is secured to tension beam members, and wherein the shiftable sealing means is selectively lockable to the tension beam members at selected locations therealong.
These and other various objects and advantages of the present invention will become more fully apparent as the following description is read in conjunction with the accompanying drawings.